GNyberg is correct. If you press the ignore button, it ignores all the ancestry trees that have been found to match.
This "problem" stems, I think, because if there are 10 records that ancestry thinks might relate to your person, then ancestry shows it as 10 hints; and thus you can accept or ignore each one individually or leave some as hints maybe to be further examined later before making a decision.
However when ancestry finds 10 family trees that ancestry thinks relates to your person then they are all rolled together as 1 hint, and while you can choose to accept only some of the trees in the hint, ancestry then automatically assumes that you are rejecting the other trees. Personally I find this highly annoying particularly when I find that there is one hint for a person but on examining it, it might consist of 10, 15, 20 or more trees.
My attempts to date to raise this issue with ancestry have not got me anywhere.